It has long been known that for individuals who have limited mobility of their limbs, regular exercise can provide significant benefits. Such individuals, who may have suffered a spinal injury, stroke, multiple sclerosis (MS), muscular dystrophy (MD), or other similar injury or disorder that impairs mobility (either temporarily or permanently), may also find that their impairments can even present significant obstacles to exercising other relatively unaffected body parts.
Regular movement of all major body parts has been shown to be necessary to promote the comfort, health and general well-being of individuals suffering from such disabilities. A failure to do so can have painful, even unhealthful and dangerous consequences. For example, immobility tends to lead rapidly to stiffened and painful joints and tendons. In the longer term, atrophy of unusused and underused muscles can occur. A greater susceptibility to the formation of blood clots has been demonstrated. Long-term immobility also leads to an overall deterioration of the cardiovascular system.
By way of contrast, when impaired limbs are regularly exercised (e.g., when subjected to repeated manual extensions by a physical therapist), joints tend to become more flexible, circulation is improved, the tendency to atrophy is reduced, the heart tends to work more efficiently, and the patient tends to experience less pain and discomfort. While the benefit of such exercise is indisputable, it can require considerable time and effort of both the afflicted individual and the assistant (therapist or volunteer). In some cases, truly effective exercise of a disabled person can tax the limits of strength and stamina of the assistant.
In response, several mechanical and electromechanical devices have been designed to help in providing a practical means by which a disabled person can exercise relatively unassisted. While beneficial in many ways, these devices often have their limitations. For example, U.S. Pat. No. 4,773,399 ('399), entitled EXERCISING DEVICE, issued to Kenneth O. Richardson, describes a device for exercising the arms and legs of a person who otherwise has difficulty moving these limbs. While the exercising device disclosed in the '399 patent has proven effective, it does not afford motion of the feet comparable to that which would be achieved in walking.